A gyratory crusher of the type herein set forth has a central upright shaft that supports a crushing head but camming action to gyrate the head in a crushing chamber is provided by rotating an eccentric sleeve mounted around the lower end of the shaft. Such crushers are often provided with a piston beneath the central shaft, operable by fluid pressure to move vertically relative to the frame to raise and lower the shaft within the eccentric camming sleeve, and adjust the spacing between the head carried by the shaft and the concave carried by the frame. Examples of such crushers are shown in U.S. Pat. Nos. 2,448,936 of 1948; 2,579,516 of 1951; 2,667,309 of 1954; 3,372,881 of 1968; and 3,467,322 and 3,481,548 of 1969.
Crushers having the rotating eccentric sleeves are often made with hydraulic arrangements for lifting the concave member relative to a shaft and head that are not moved up or down for adjusting purposes. Examples of such crushers are U.S. Pat. No. 2,680,571 of 1954 and my own U.S. Pat. No. 3,396,916 of 1968.
However, removal of the eccentric bearing assembly requires that the entire eccentric assembly be removed. To remove the assembly, an upward evenly distributed lifting force must be applied to the assembly to effect its removal. It can be seen that a satisfactory purchase with a chain or wire loop sling is very difficult to obtain on the assembly. If a satisfactory purchase could be obtained and the lifting force applied by an overhead crane, upon release of the assembly dangerous situations may result. One such situation is that due to the sudden release of the bearing fit, the tension in the sling and crane is suddenly released. This can cause the eccentric assembly to release suddenly thereby endangering equipment and more seriously cause bodily injury to personnel. Another dangerous situation relates to the sling itself. Because of the difficulty of obtaining a satisfactory purchase, the sling could slip loose causing damage and/or injury.